XCOM: Enemy Unknown by Firaxis (Sid Meier's company, the makers of Civilization) will place you in control of a secret paramilitary organization called XCOM. As the XCOM Commander, you will defend against a terrifying global alien invasion by managing resources, advancing technologies, and overseeing combat strategies and individual unit tactics.

XCOM: EU (not to be confounded with XCOM, the upcoming XCOM First-Person (?) Shooter by 2K Marin) is a turn-based tactical and strategic game based on the 1994 classic X-COM Ufo Defense. On a strategic layer you manage your resource and let time pass on, while on tactical missions you steer your individualized squad of elite troopers in turn-based combat.

What's special about XCOM is the attachment to your individual units (that you can name after friends, family, famous persons or simply people you hate and send into harm's way) and that you can actually lose the game! It's a gripping game that is playable again and again.

Disclaimer: All these tips and strategies are only valid on difficulties Classic and higher. On Normal (or Easy *gasp*) you can pretty much do what you want - it's very hard to lose the game there.

Field Manual X-I 01 [Base Building / Manufacturing Strategy]

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Preamble: Wars are won through logistics, not through the valor of men. With this in mind it's on the strategic level that you win the game. Until very late in the game, this will be plagued by bottlenecks and hard decisions.
What you want to do: Harness your resources and reserve enough Weapons Fragments (WF), Alloys, Elerium and credits to build the war-critical items you need.
What you do not want to do: Build facilities, items, or commission Forge projects you do not immediately need. Don't ever sell Alloys, Elerium or WF.

MONEY

You will earn money at the end of each month based on satellite coverage, through random Council missions as well as Council requests (producing something - the reward may be non-monetary, though). In a pinch you can sell items you recovered from you missions on the grey market (see above - don't sell Alloys, Elerium or WF, if you can avoid it). Some items are only meant for sale (and are marked as such in their description) and you can probably do without corpses in excess of ten for each type.

In the early game the money from the Council will be your primary income. This means you want to build a(nother) Satellite Uplink as early as possible and then build the Satellites to go along with it. Plan ahead to build Satellite Uplinks in a square: That way you can do without a Satellite Nexus and by virtue of the adjacency bonuses can guide twelve satellites, giving you enough to cover all continents save Africa. If you get a choice, try to get Asia (gives you half of on OTS and Foundry projects, but requires four Satellites) and/or South Africa (gives you instant autopsies and interrogations with just two Satellites) covered completely for their bonuses.

Do not build a Satellite at §100! Even before you build a Workshop, after you gain ENG through your first mission, that price will drop to about §77 and decline steady even further later in the game.

Building a Satellite will take 20 days. You want to launch it briefly before a Council mission, because along with the money, it will also reduce Alien Panic over the country you launch it by two panic levels. This is the best way to avoid countries leaving the project. Deployment takes a few days, but that is not important for this purpose and only serves as a reminder to you to make sure to have fighter coverage for that continent.

FACILITIES

In XCOM building new facilities is either necessary to advance to the next stage within the narrative of the game or simply gives you bonuses.

In your first mission have have selected the one that gives Engineers as a reward since you need 6 ENG to build a Workshop, which in turn gives you 5 ENG to surpass the minimum of 10 ENG that you need to build Carapace Armor.

The next most important facility should be the Officer Training School (available once one of your troopers has reached the rank of Sergeant). This will unlock the fifth slot (at Sergeant / §50) and the sixth (at Captain / §75 ) of your squad. This should be the absolute priority.

After that you should and plan the next Satellite Uplink, possibly followed by the Alien Containment facility (depending on your research strategy).

Thermo Generator §200 -> +20 Power, , Adjacency Bonus +2 Power

Laboratories are never needed and you will only build one or more Power Generators if you have a desperate need of Power and not Steam upon which to build the Thermo Generator or not enough resources for the Elerium Generator.

There a few special facilities:

Officer Training School (build as soon as possible)

Alien Containment (story-based - build once your troopers have a chance to survive and after you are done with the Satellite(s) you inted to launch for the month in question)

Foundry (build after you have a consisten influx of money and ressources)

Hyperwave Relay (story-based)

Psionic Labs (story-based)

Gollop Chamber (story-based)

FOUNDRY

The Foundry facility offers 18 upgrades to your weapons and gear. All of those take time and resources to complete, so you should only start to get into it once your financial situation is a bit secured.

The interesting ones are (all have pretty stiff requirements in additional time, § and extraterrestrial materials not listed here):

Alien Grenades (you need to capture an alien carrying one, after research you get an infinite supply of them, basically replacing your fragmentation grenades)

Ammo Conversation (for the Ammo Whisperers amongst you... you need a six Muton corpses, their autopsy and double your magazine size with it)

The Foundry also tempts you to put a huge amount of resources into SHIVs (small tanks). Don't - unless your experienced troopers bought the farm. If you have to rebuild your cadre, you can use one or two tanks to provide additional fire power. Another reason not to go into SHIVs right now is that there a few bugs involving them that can make them unusable during a mission.

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Research in this game is important, as it will both allow you to build items you need for survival, as well as technology that advances the story of the game.

That being said, it is rarely a bottleneck, even without you ever building a laboratory (that improves research speed by 20%). Especially late in the game it frequently happens that you run out of projects to research.

In the beginning of the game, the order in which you research does make a lot of difference, though, especially on the harder difficulties or Ironman.

Personally I find getting my troopers into Carapace armor as early as possible, in order to survive one or even more hits. With this in mind, I recommend this order of research (Weapons Fragments will likely be the second as you lack the necessary number of Alloys):

Alien Materials (this enables the production of the Nano-Fiber Vest, which you can use in the Grenades slot to give your trooper two additional HP - it is of limited use, so don't build too many of those).

Carapace Armor (You need to have recovered at least 10 Alloys from an UFO for this, so it's likely that you have to push this back. Once you do have 40+ Alloys, research it and build Carapace Armor as early as possible. Each Carapace Armor consumes another 15 Alloys and costs §25, so be sure you have those available).

Weapons Fragments (This enables the SCOPE, only build one for a Sniper you use)

Beam Weapons (This enables Laser Rifle, the most needed early game weapon, especially on Classic and above)

After this you have several options:
1. Men in Black

This basically opens up the story missions that will lead to the crucial Alien Base mission. Having the Arc Thrower allows you to capture enemies alive (after you have built the Alien Containment facility). Besides the importance for the story, the aliens also give you bonuses on research). Not having the bonus likely doesn't pose any problem, though.

1. Xeno-Biology
2. Arc Thrower
3. Interrogations

Research bonuses for captured aliens (once interrogated):

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Sectoid -> Beam Weaponry

Sectoid Commander -> Psionics

Thin Man -> UFO Tech

Floater -> Basic Armor

Heavy Floater -> Flight Tech

Muton -> Plasma Weaponry

Muton Berserker -> Armor

Muton Elite -> Weapons Tech

Ethereal -> All Tech

Don't bother with autopsies - they don't give you any real benefit that you need at this point. They will become interesting only once you decide to build a Forge.

2. Aerial Superiority

In order to protect your Satellites you want to have a Firestorm Interceptor based at each continent that you cover with Satellites. Start as early as possible with your research:

Having a Firestorm protecting each continent in early to mid-game pretty much guarantees the UFOs going down, buying you a little bit of time and securing your funds at the end of each month. You can equip the Firestorms with Laser Cannons (gained through Heavy Lasers research), for more punch. You definitely want this before going for the Overseer Craft, otherwise it'll run circles around you. Getting to the technology early gives you enough time to build the four Firestorms you need, too.
3. Armored Warfare

Getting your troopers into Titan Armor will keep your experienced soldiers alive and kicking until you get complete Satellite coverage and enough money to buy the complete OTS tree.

Once you have finished these three research arms, there will be quite a few choices, but basically all of them are good. If you build a Forge (at this point you should, considering there are many good updates for the equipment you are using to be had), do the autopsies now. Beyond that you may want to finish out your Weapons research to give your Snipers better Rifles (Laser), or go into Plasma Weapons as early as you can (Light Plasma Rifles are equivalent to Laser Rifles in all aspects).

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While you lose the game on the strategic level, you win it on the tactical level, and this is where you will actually spend the most time on.

Each mission will have an objective that you will have to fulfill to make the mission a success, though that success will be tempered by how well you do on your secondary objectives.

There are several mission types, the most common being:

Abduction missions

UFO Recovery missions on shot down UFOs

UFO Assault missions on landed UFOs

Escort missions given through the Council

Bomb missions Disposal given through the Council

Terror missions trying to save civilians

Story missions (Base Assault, Overseer UFO, Temple Ship)

What is common to all of them is that you need to eliminate all aliens opposing you (even on Escort missions you can't just fly away, which doesn't make sense at all, I know).

At Classic and even more so Impossible level you start out with four soldiers that you can send, and through perks in the Officer Training School facility you can extend this to five (§50, you need a soldier with rank Sergeant) and six soldiers (§75, you need a soldier with rank Captain). This should be one of your early priorities.Fundamentals of Tactics

Tactical Maneuver: Fire without movement is indecisive. Exposed movement without fire is disastrous. There must be effective fire combined with skillful movement.

Combat Power: The ability of a unit to fight.

Combinations: The power of combination creates dillemas that fix the enemy, overwhelming his ability to react while protecting your own internal weaknesses.

Advantage: Seek every opportunity to exploit your strengths, while preventing the enemy from exploiting his own strengths.

Maneuver:
The US Army differentiates between Movement and Maneuvering, the first being without direct enemy contact, but anticipating it, the latter basically being movement under fire.

Movement
In XCOM each of your soldiers basically has two moves/actions. You can take them one by one, or expend them both in one mad dash.

The basic rule here is: Don't dash.

You know there will be enemies on the map, and exposing one of your soldiers to the enemy without even the ability to shoot back (which you only have if the dash is with an Assault trooper using Run and Gun), is a valorous form of suicide, at best.

You dash a soldier that needs to get back into the perimeter of his fire team, for example a Sniper that had hung back and now has lost any useful line of sight because the fire team has advanced into a build or around a corner.

You dash a soldier if there is not decent Cover to be had and by extending the normal move you will gain he benefit of having full cover rather than half or none.

You may dash an Assault soldier with Run and Gun to flank an enemy for a kill shot, but remain aware that you may expose this soldier if the shot doesn't hit, and that the soldier may also reveal another enemy group, or even several, leading to a major tactical disadvantage.

Instead of dashing, you want to move soldiers from the back into the next best cover in the direction you want to go with one move, giving them the ability to shoot if they encounter enemies or go into Overwatch to protect against moving patrols on the enemy turn. You start with the soldiers that hang back, because that makes it most likely that your other soldiers will be able to engage the same target(s) that the moving soldier reveals during the same turn.

With your last two troopers don't ever advance further than your perimeter, i.e. don't move into a position that extends the current area of the map that your soldiers can already see.

Maneuver
Once an enemy is revealed to you, you want to eliminate them as quickly as possible, without exposing yourself. Your goal in maneuvering is to get a better vantage on the enemy, ideally without sacrificing your own defensive position.

Keep in mind that the alien may be on Overwatch. In that case it maybe the best move to first move an Assault Trooper with Lightning Reflexes through the enemy's field of vision, for him to expend his Overwatch action futilely.

Other than that, try to flank the enemy towards one side. In general go for one, to get something like an L-shaped setup of your squad, in order to minimize the exposure to yet unseen enemies.

Always plan ahead for the case that your shots don't hit, and don't leave maneuvering soldiers out of cover.

Combat Power:
In XCOM combat you want to destroy or suppress your enemy with direct and indirect fires. Success follows a few simple rules.

Mass the effects of fire

Destroy the greatest threat first.

Avoid target Overkill

Employ the best weapon for the target.

Minimize friendly exposure

Prevent fratricide

Develop contingencies for diminished capabilities

Mass the effects of fire
The basic truth in XCOM is: Only a dead alien is a good alien. If you only wound an alien, he will shoot back and potentially kill one of yours. On any given turn identify which of your troopers have line of sight (LOS) to any target, and estimate which target you may get LOS on by maneuvering.

If your Squadsight Sniper only has one target available and it is unlikely that he will gain line of sight to any other, start by using this soldier.

If you have high-percentage shots against enemies out of cover, and you can shoot at them without leaving good over, do so. Concentrate your fire on these targets until they are eliminated.

Destroy the greatest threat first.
Know your enemy and identify the largest threat.

A nearby Chryssalid as a force multiplier has the potential to attack a nearby soldier in weak armor the next turn, and even use him to produce another enemy.

A Cyberdisk or Sectopod can be fearsome if left alone. On the other hand if you have only one shot left that will certainly not eliminate the Cyberdisk, it may be best to shoot at the Drone in order to minimize the shots your soldiers will be exposed to the following enemy turn.

On the other hand, a Berserker standing exposed at the edge of your field of vision may not be the biggest threat - he will need another turn to get close to you, continually exposing himself while those Muton soldiers that took cover may use their plasma rifles against you.

Avoid target Overkill
Unfortunately the game is not programmed well to allow for this. It happens frequently that all your soldiers on Overwatch will shoot at the first target they see, leaving no shots for a second one.

What you can do is having soldiers on opposite flanks be on Overwatch, or have the odd soldier reload instead of go on Overwatch, if you feel the current protection is sufficient.

Employ the best weapon for the target.
You face a Muton and a Cyberdisk, and your Heavy has the HEAT perk? Of course you want to direct his attacks against the Cyberdisk, and early, so you can do the most possible damage early. That allows you to either do follow-up attacks with others soldiers, or direct their attacks to other targets. Expending a rocket on a Cyberdisk with just 2 HP left would be suboptimal if you had expended multiple other attacks against it.

An enemy with only 1 HP left is often best shot with a pistol, saving you ammunition on your main weapon, which in turn might prevent you from having to reload with the next enemy just coming around the corner.

Minimize friendly exposure
Constantly seek cover as good or better as the one you have (see maneuvering). If you overextended and a soldier is close to the enemy without support, consider to Hunker Down instead of using an attack that will only serve to wound an enemy with no chance to kill him.

Prevent fratricide
In XCOM friendly fire only happens when your troopers panic and fire wildly, or by explosives not landing on target. Be careful when using explosiv ordinance that your troopers are as far from the area of effect as possible.

Develop contingencies for diminished capabilities
Some missions will be tough even when you have a full contingent of six experienced soldiers available. But what do you do when some of them can't be on a mission due to wounds, or when in the course of a mission soldiers are killed?

Consider retreat as a possibilty! Sometimes it's better to save the trooper to fight another day than to get them killed uselessly.

Combinations:
Even in the real world soldiers are looking for "combos". Generally this means using combined arms (calling artillery, air strikes, etc.), which we have only few of in XCOM.

There are a few combos, of course, many based on specific perks your troopers may have:

Squadsight - the most simple of combos is having a Sniper with Squadsight stay in a position of out sight of the enemy but with a good field of fire. Once on of your other troopers sights an enemy, this Sniper will be able to engage even if the target usually were out of his range. This can be extremely powerful with high-level perks like Double Tap or even just with height advantage.

Holo-Targeting - early in the game the Heavy can select the perk Holo-Targeting. If this Heavy engages a target, regardless of hitting it or not, all other soldiers shooting at the same target in the same turn will gain +10 to their AIM.

Explosives - Grenades, Alien Grenades and Rockets have fixed damage. While their damage may not be enough to outright kill a target, as a side benefit it destroys all cover it has. So use these first, and then enjoy the much better percentages your other soldiers have to hit the same target. If you have a high-level Sniper that selected In The Zone instead of Double Tap, he may even attack all those targets that are out of cover without that counting as an attack.

Advantage:
You try to maximize your advantages over that of the enemy. In the most basic sense that means you want to generate situations where you have more attacks potentially doing more damage on any given turn than your enemy.

You don't want to...

Move up your Heavy or Sniper as the first action, because their best offensive power (Rocket and Sniper Rifle) is only accessible if they haven't moved yet.

Divide up your forces unless absolutely necessary. If you do have to split up, try to organize them into two fire teams that can support themselves.

Bunch up your forces in a small area when facing enemies carrying Alien Grenades (Mutons, Heavy Floaters, Cyberdisks)

You want to...

If you are not pressed time-wise (as in Bomb Disposal or Terror Missions), after you already heard an enemy you want to set up a trap with Overwatching soldiers in good cover and wait a turn or two to see whether he maybe does not wander into your trap on a preset patrol route. This does not apply to UFO commanders.

If you have found a good position to set up an ambush, with only bad terrain in front of you, consider to send up a Support trooper with the Sprinter perk and possibly an armor that enchances movement forward and draw him back into cover once he has alerted a group of enemies.

A Continental Fellow requires you to win the game in each of the five locations (North America, South America, Europe, Africa, Asia), therefore you'll need 5 playthroughs for the platinum. Incidentally your first playthrough will likely be the longest, because you want to make sure to pick up a lot of lengthy trophies along the way (those marked with green exclamation marks - see below). Absolutely make sure you get a chance for Ain't No Cavalry Comin'.

All absolutely critical trophies as well as the hardest ones are marked with the red exclamation marks - others are used to note trophies best achieved in the first and second playthrough (see below).

Playthrough 1: Normal. Make sure you pay attention to and read the trophy descriptions marked with the green exclamation mark. These are best done on a Normal playthrough using the Tutorial option. Take your time, there is no need to do story missions until you wish to advance.

Playthrough 2: Classic. Make sure you pay attention to and read the trophy descriptions marked with the yellow exclamation mark. These have to be done on the Classic playthrough. Take your time, there is no need to do story missions (starting with the Alien Base Mission) provided you are not in danger of losing more Council Nations. If you missed any of the green trophies on the first playthrough you can probably do them on this playthrough, too.

Playthrough 3: Classic Ironman. Play the game carefully and deliberately. You only have one save game and you can definitely lose the game, necessitating for you to start over! Don't worry about anything else.

Playthrough 4: Impossible. Turn on Autosave and make liberal use of manual Saves as well. Impossible is all about getting a good start, keeping a functioning Squad including substitutes alive and managing panic levels. Note that enemy hit and critical hit percentages are artificially raised, so keep your trooper's heads down (for more see Tips & Strategies).

Playthrough 5: Mop-Up. If you managed to get all trophies except for A Continental Fellow, just play what you want with the base on the last continent you haven't played yet. Otherwise use this to get the missing trophies.

No Looking BackBeat the game in Ironman mode on Classic or Impossible difficulty

In order to get this trophy you need to win either Classic Ironman or Impossible Ironman. If your goal is to get the Platinum Trophy and not to merely punish yourself, do this on Classic Ironman, not on Impossible Ironman. All Tips & Tricks above are designed to help you through Classic Ironman mode.
The trophy is difficult enough that you will dedicate a whole playthrough (I recommend the third) to it.

At the beginning of a game, in addition to the difficulty you select, you can also set Ironman mode under 'Advanced Options'. This effectively reduces your save games to one single Autosave. So if you botch a mission, there is no turning back, troopers you lose on the battlefield are dead, permanently. Obviously this makes games very much harder to win. That's XCOM, baby.

Note: The soldiers you begin the game with have only 4 HP on Classic difficulty. Soldiers you hire subsequently have 6 HP (this may be a glitch). Soldiers hired later therefore are a bit more durable and "valuable".

If you'd like to see Classic Ironman in action, I have recorded my complete run (as far as it went), that included 33 trooper deaths:

XavierMind Control an Ethereal. Single player only

There is no Project X. And if there were, you wouldn't remember it. They will make sure of it.

This will only be possible very late in the game. Ethereals are notoriously hard to control, so make sure to stack the odds in your favor.

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You will need:

A psi-enabled soldier with a high Will, with Mind Control - a third tier psionics perk - selected;

An Ethereal, which you can find as the Commanders of very late game UFOs (replacing the Outsider / Sectoid Commander you previously encountered);

All the Will enhancing technology you can bring (PSI armor, Mind Shield, Will-enhancing Smoke Grenades).

This is best done on a smaller UFO. Make sure you have eliminated all other opposition, before entering the downed UFO's bridge. Wound the Ethereal (use pistols or grenades, if your weapons are too advanced), then try to Mind Control him.

Unfortunately wounding the Ethereal or raising the will of your Psyker doesn't seem to work. On Classic the chance to Mind Control the Ethereal was only 38%, which fortunately worked on the second try. Bring a lot of Medikits, just in case.

Humanity's SaviorBeat the game on any difficulty

Just do it, go all the way to the end. It may not appear easy to you, but it will come. And then you will learn about the true multi-dimensional nature of our existence...

You will likely get this on your first playthrough on Normal. Remember that when the final mission is available, you can't go back after that (barring loading a save game), so make sure you have all the trophies marked with a green exclamation mark!

Earth FirstBeat the game on Classic difficulty

You see - there are different dimensions. Those who touch us are similar to our own. Your girl friend might be called Carol instead of Corinne, and she maybe a hot brunette instead of a hot blonde. But they are also invaded. And we can only win the war, if we win it everywhere. Some dimensions operate under slightly different laws of physics and Charlie dimension is one of those that don't exactly favor us humans. We only send our more experienced operatives there.

Tread carefully and try to keep your operatives alive. The heavy use of SHIVs is recommended. And do follow Field Manual X-I 03 to the letter!

You can get this along with "No Looking Back" if you play in Ironman mode, but it will be harder, and you will need to do five playthroughs in any case, so take it easy and make use of save games if things get too much out of hand.

If you find you are having trouble finishing on Classic, there is an exploit, detailed under Our Finest Hour.

Our Finest HourBeat the game on Impossible difficulty

You don't want to go into India dimension. Only volunteers go there, but almost none come back. It is the one dimension we simply cannot win in. If this war were a video game, this would be the Easy setting. For them.
If you absolutely insist, this is what Field Manual X-I 03 has been written for.

Impossible is very, very hard. Aliens shoot better and get a much higher chance for critical hits. Nations are dissatisfied much easier. It's going to be a real challenge to keep your troopers alive and the Council nations happy.
In this playthrough (I recommend the 4th, starting in Asia), just concentrate on staying alive and winning the game.

Note: The soldiers you begin the game with have only 3 HP on Impossible difficulty (+1 for the beginning armor). Soldiers you hire subsequently have 6 HP (this may be a glitch). Soldiers hired later therefore are a bit more durable and "valuable".

You will lose soldiers, even with reloads, even if you play perfectly. The aliens have highly raised abilities for hitting and scoring criticals. Make sure you initially protect your experienced troopers until you have a Sergeant. Build the Officer Training School and expand your squad size to 5 (That's why you should build the base in Asia for this run). Get Laser Rifles as soon as possible. Build one satellite and use it at the end of the month to prevent one country from leaving XCOM.

Tactically give your troopers a fighting chance and keep them alive during missions (keep a tight perimeter, use lots of high cover, keep your troopers in a formation so they can use overlapping fire, but not so tight as to represent an irrestible target for alien grenades, and don't scoff at the "Hunker Down" option). Have a look at Field Manual X-I 03 for some more indepth treatment.

If you continue to have troubles at this difficulty level, there also is an exploit, found by Lasombra (as of yet unconfirmed), explained step by step:

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Originally Posted by Lasombra

Load any game just before the temple ship battle. Change the difficulty to the desired setting. Do any non-temple mission. This will change the base difficulty to that new setting. Do the temple mission without dying or needing to load a save. Wait until the 'Victory' victory stat screen the end and the trophy will unlock for that difficulty.

If you load a game, no matter if the trick was done or not, the game reverts back to its base difficulty. Example: I started the game on Easy at the very start (mission 1), thus the games base difficulty is easy. If you die during the temple mission you need to redo the entire process mentioned above again.

So far I haven't verified it - and the problem is that you can't reload the temple mission and need to do the whole map on Impossible difficulty. On the plus side it easily gives you optimally equipped troopers to try the mission with.

Lone WolfClear a UFO crash site with one soldier on Classic or Impossible difficulty

"Okay. We have shot down a UFO, Alpha Squad is going to go in and make sure none of those alien mother*bleep* have made it down alive. Yes, Dr. Vahlen, and scavenge whatever alien video games are left unbroken. Okay, Mulller... Muller? Where is Muller?"
"He is assaulting the UFO, Central Officer Bradford, sir."
"WHAT? But this is the mission prep."
"He said, by the time you were finished talking, he'd be back."

This is a tricky one, and I really recommend to do it on Classic rather than Impossible.

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The target of choice should be shot-down small UFO, relatively early in the game, definitely before you do the Alien Base mission. If you do this very early in the game, you can try a Support trooper who already has the Field Medic perk. Deep Pockets obviously help.

Carapace Armor is a must and if your Support trooper has reached the rank of Major take along the Chitin plating in the second slot, raising your HP by another four. With a little bit of luck you'll only have to contend with Sectoids and Floaters.

Tactically go in, if you are spotted, run back into full cover. Wait for the aliens to come to you. If you are wounded, pull back and heal, then try again.

If you have to try this later in the game (again: Before you do the Alien Base mission), you can try an Assault trooper, Support trooper or even a Sniper in Ghost Armor to get you out of tight spots.

Bada BoomKill 50 aliens with explosive weapons

Yes, big Bada Boom. Remember the redhead with the white chestband for a bra? Well, it has been proven that those alien suckers are not immune to it, so use it. Use your grenades or your rockets. Don't make 'em bleed. Blow 'em to pieces!

While Dr. Vahlen reminds you not to use explosive weapons, because then you do not get corpses or other goodies of those aliens, in higher difficulty playthroughs you'll use them, because you need to kill them before they kill you any which way you can.

At the end of each playthrough you'll be shown how many xenos you eliminated via explosives. The count for this trophy carries over to the next playthrough. Depending on your style of play this will unlock somewhere between your second and your fourth playthrough.

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There are five explosive weapons in the game:

Frag Grenades

Alien Grenades (through Foundry)

Rockets (Heavy Perk)

Shredder Rockets (Heavy Perk)

Blaster Launcher

Also exploding cars may count as an explosives kill.

Welcoming CommitteeKill 150 aliens

Perusing the records, eh? Well, shooting down 5 alien craft makes one of our pilots an ace. For you I'd rather have you bring back all of your squad mates. That's more of an achievement. Killing aliens is part of your job description - here is no reason to keep track of them, it will come naturally.

Pale HorseKill 500 aliens

In the records room again? Shooting to become a REMF? Let me tell you - in Vietnam the brass thought counting dead bodies was a great way to make sure the US were winning the war. Didn't work. It doesn't matter how many you kill, you need to cut off the head. Killing any number of them will come naturally in the process.

The count carries over from playthrough to playthrough. You will likely get this naturally in the course of your second playthrough.

Ain't No Cavalry Comin'Have a soldier survive every mission in a full game

This in fact is one of the most difficult trophies to get and best done on your first playthrough. One of the four soldiers in your initial mission has to participate in every single mission of the game, and survive it.

Definitely try to do this on your first playthrough, and keep track of those four initial soldiers. You can do this by giving them special names like "Must SURVIVE" or something similar.

As A ScalpelEarn the "Excellent" rating in every performance category on a terror mission

"We're on an express elevator to Hell, goin' down!"

To get this trophy you need to fulfill three objectives:

Kill all xenos.

Have none of your troopers killed.

Save enough civilians to get an excellent rating. You will lose some civilians, so don't sweat it, too much. A rating of 14/18 saved is sufficient.

In order to achieve this you need to depart from the usual careful approach. Selecting your squad is important, due to the special circumstances:

Assault: Should have Lightning Reflexes.

Heavy: Rockets help with establishing sight lines, but if you have the Danger Zone perk, this might actually work against you.

Sniper: Absolutely needs to have Squadsight. If you opted for another, swap him out.

Support: Sprinter helps a lot with getting to the civilians quickly enough.

At the start at the mission have a Support Trooper dash into a direction where your Squadsight Sniper has a good field of view. With a little bit of luck you'll draw immediate attention from the xenos. Eliminate that first batch with your Sniper, a Heavy Weapons Specialist or a Run & Gun Assault Trooper.

Afterwards proceed with gusto, but do not throw caution to the wind. If you need to split up, always build fireteams of two or three troopers, never have somebody go Lone Wolf.

If you do not achieve this on your first terror mission, don't worry, there will be more chances. Of course you can always reload, but usually that won't be necessary.

EdisonIn a single game, complete every Research Project

You will receive this trophy late in the game. If you have no research options left and haven't received the trophy yet, check below.

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The last research projects you are likely to research are:

Story-based research: Ethereal Device is available after you intercept the Overseer UFO, and it enables PSI Armor;

Fusion Lance - you get this option once you have recovered a Battleship Class Fusion Core. Battleships only appear very late in the game. It's heavily recommended you have Firestorms with advanced weaponry deployed by then;

Guided Fusion Launcher - affectedly called the "Blaster Launcher", you get this option once you have recovered a Battleship Class Fusion Core;

Any missing autopsies or interrogations. Refer to All Employees Must Wash Hands... to see a full list of aliens, and which ones can be captured alive.

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Sectoid

Sectoid Commander

Thin Man

Chryssalid *

Cyberdisc *

Drone *

Floater

Heavy Floater

Muton

Berzerker

Muton Elite

Sectopod *

Ethereal

Beyond the VeilFind a soldier with the gift

"Grandma, why do you have such purple eyes?"

You need to identify one of your troopers as psionically gifted. This is story-based and you can't miss it.

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This is done by building a PSI Lab and then testing your soldiers in it. The capacity of a PSI Lab is three, and during the 10-day duration the soldiers you test are taken out of your rotation. If they carry rare equipment, make sure to unequip it first, in case there are missions during that time. Troopers with higher Will ratings have a higher probability of having the gift.

You can build the PSI Lab after interrogating a Sectoid Commander. The first Sectoid Commander is found in the Alien Base Assault. If you do not manage to take that one alive, UFOs shot down after the Alien Base mission will usually have one or more Sectoid Commanders on their bridge.

Prisoner of WarCapture a live alien

Yes, it's pretty creepy down there. They have some Russian scientist who swear during the Cold War they developed a mechanism to extra information from any creature by applying just the right incentives and measuring brainwaves. Just before death the images intensify and can be put on a screen. If that's not the definition of creepy...

This is story-related, you cannot miss it.

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After Xeno Biology and Sectoid Autopsy you can research the Arc Thrower technology. Afterwards, once you build one (or more) of these you need to get within two squares of an alien. At 3 hp left you have a 70% chance of stunning it, increased by 10% per hp less than 3. Getting there is tricky, a Support trooper with Sprinter or an Assault trooper with Lightning Reflexes is helpfun. Run & Gun unfortunately doesn't work, since that would constitute using an item.

The GatekeeperStun an Outsider

"We are supposed to bring back a being consisting of pure energy? Are you serious, Bradford?"
"That's Central Officer Bradford for you, trooper."

This is story-related, you cannot miss it.

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You find Outsiders on the bridge of downed Scout ships. They have 3 HP on Medium (5 HP on Classic, use Pistols to bring them down to a manageable level) - which makes them ideal to be stunned (don't bring heavies, and switch to pistols first to increase the chance). Try to take care of all other alien threats in the mission and then move up to the UFO's bridge - forfeiting any Overwatch stances - and stun him.

If you have enough troopers in sight, line up a pistol shot to bring the Outsider down to 1 or 2 HP to improve your chances. And, yeah, well, forgetting to bring an Arc Thrower sort of invalidates this...

X Marks The SpotUncover the alien base's location

"Ever heard of a Mind Map? Well, in this case our experimental encelograph translates a scan of the subject's synapses into spatial relations."
"Huh?"
"It'a map."

This is story-related, you cannot miss it.

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Once you interrogate a live alien, you are tasked with capturing an Outsider. Once that is accomplished you can research Outsider Shard. Consequently the location of the Alien Base will be revealed.

There is no penalty for for not taking this mission immediately! Before you rush into, make sure you have completed all other tasks you want to accomplish. The game tends to get significantly harder after you assault the alien base, due to the new creature types appearing.

See All, Know AllBuild the Hyperwave Relay

This is story-related, you cannot miss it.

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Once you have recovered the Hyperwave Beacon from the Alien Base, you can research Hyperwave Communication. This in turn allows you to build the Hyperwave Relay as a facility in your base, leading to the next story mission.

On The Shoulders Of GiantsBuild the Gollop Chamber

This is story-related, you cannot miss it.

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Once you have recovered the Ethereal Device from the Overseer UFO, you can research, well, Ethereal Device. This in turn allows you to build the Gollop Chamber as a facility in your base, leading to the next story mission. The trophy will unlock once construction of the Gollop Chamber is completed.

Note: The name of the Gollop Chamber is an easter egg of sorts (referenced to in the explaining text, too), referring to Julian and Nick Gollop, the creators of the original game.

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In order to unlock the New Fighter Craft you first need to capture and then research Alien Nav Computer and UFO Power Source.

Eye In The SkyLaunch a Satellite

With all the junk sitting in orbit above our planet we can hide a few spy satellites up there. From there we can spot the little grey bastards and give them a warm welcome. Make sure you have a crack squadron of interceptors in the same area, though.

Within the course of the expanded tutorial you will be gifted a satellite. Launch it. After a few days it will be deployed and the trophy will unlock.

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Once you have recovered the Ethereal Device from the Overseer UFO, you can research Ethereal Device. This in turn allows you to build the Gollop Chamber as a facility in your base, leading to the next story mission.

All Together NowGet satellite coverage over every country on one continent

"Over time we'll have a surveillance network that no mouse will be able to creep through." - Central Officer Bradford

This unlocks once you assign a satellite to each country on one of the continents (the satellites don't have to be deployed).

You will want to have satellites early in the game, but this will really only become feasible after you research the Alien Nav Computer, as that allows you to build the very expensive Satellite Nexus (4 Satellites + Bonus).

The Temple Ship cannot be shot down and doesn't count.

Man No MoreBuild a suit of powered armor

Poison ControlCure poison on five soldiers in a single mission. Single player only

"It works like the bite of a King Cobra, only these guys don't even have to bite you."

Over the course of a single mission, you need to be poisoned five times, and cure it.

In order to get poisoned, you need a Thin Man to spit poison (very unreliable), or you need to move into the poison cloud that is generated when you kill one of them.

Titan Armor and Medikits prevent you from becoming poisoned in the first place, while you obviously need at least five Medikits in the squad.

The easiest way is to take two Support troopers with the Field Medic perk gained at Sergeant rank. The other troopers can not carry a Medikit or wear Titan armor. Assault troopers are best, because they can run up to a Thin Man and still kill him using Run and Gun, while being poisoned in the process.

When you encounter your first group of Thin Men, kill them and deliberately get two or three of your troopers poisoned. Stop and get the Poison healed. Advance to the next group. Rinse, repeat.

This basically works on any map where you encounter at least two groups of Thin Men, but there is one mission that seems to be made for this:

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In the late game you may get lucky and receive the Council mission 'Asset Recovery'. In this special mission you are tasked to find out why 'strange men in suits' are hanging around a graveyard. This means you have a relatively small map with 12-15 Thin Men and no other aliens. Other Council missions work as well (the rescue or bomb missions), but there you have to pay attention to the rescuee or the bombs, which makes them just a little bit harder.

Save the game before going on the mission, and then follow the advice above.

Here is an example of doing it successfully:

Krabban_ provided another late game method involving psionics:

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The poison control is very easy:
I did it on a council mission. Just make sure you bring a psi-soldier and a couple of medkits.
The first group of thin men you run into, mindcontrol one of them and kill the rest.
Bunch together your soldiers and have the controlled thin man spit poison on them.
Make sure your soldiers is not equipped with titan armor or other armor that are immune to poison.
Then just cure everyone who has been poisoned. Rinse and repeat if necessary

We Happy FewComplete a mission without losing a soldier

The motto here is 'Leave no man behind'. Sometimes in war it's inevitable, but you fight better when you know that somebody will at least attempt to get your sorry behind out of trouble, when the dirt hits the fan. The same of course is expected of you!

You can get this as early as the second mission (in the extended tutorial). Just bring all of your soldiers back alive.

OppenheimerStaff the Research Labs with 80 scientists

"How many scientists do you need to screw in a light bulb? - 80"
"Why?"
"No idea, do I look like I understand the theory behind it?"

Other than in the classic 1994 version of XCOM you now cannot buy Scientists. The only sources are missions, the end of month Council report where you get Scientists and Enginneers based on satellite coverage, and the occasional Council Request. This trophy is best done on your first (Medium) playthrough, because on higher difficulties you will be more focused on just winning the game, and Engineers become much more important.

When you are face with a choice of what mission to accomplish, your first criterion should be whether you need to manage the Panic Level of the nations the available missions take place in. Your second criterion should be the possible rewards.

For this trophy you need to place an emphasis on gaining Scientists rather than Engineers, Credits or Troopers, and you need to avoid going on the final story mission that ends the game. Do enough missions until you have 80 Scientists and the trophy will unlock.

One Gun At A TimeStaff the Engineering Department with 80 engineers

"How many engineers do you need to screw in a light bulb? - 80"
"Why?"
"Easy: One to do the job, the others are busy playing computer games."

You cannot buy Engineers either. The only sources are missions, the end of month Council report where you get Scientists and Enginneers based on satellite coverage, and the occasional Council Request. This trophy can may best be done on your first (Medium) playthrough, because on higher difficulties you will find yourself be under much more pressure to finish the game before the game finishes you.

When you are face with a choice of what mission to accomplish, your first criterion should be whether you need to manage the Panic Level of the nations the available missions take place in. Your second criterion should be the possible rewards.

For this trophy you need to place an emphasis on gaining Engineers rather than Scientists, Credits or Troopers, and you need to avoid going on the final story mission that ends the game. Do enough missions until you have 80 Engineers and the trophy will unlock.

SkunkworksIn a single game, complete every Foundry project

"Hey Q, you got any new toys for us?"
"My name is Shen. Dr. Shen."
"Well, to me you really look like Q."

Complete all Foundry projects and after the last one is complete the trophy unlocks. If you are looking which ones are missing yet, look below.

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Once you complete the research for Experimental Warfare you can build the Foundry. If you selected Asia for your base, all Foundry projects cost 50% less. On a Normal playthrough you will be easily be able to complete all of them with any base, though, it will just take a little while to get the necessary materials, especially Weapons Fragments.

There are 18 projects that you can complete:

Heavy Weapons Platform

Alien Grenades

Improved Medikit

Improved Arc Thrower

Advanced Repair

SHIV Laser

SHIV Plasma

SHIV Repair

Drone Capture

Ammo Conversation

Advanced Flight

Advanced Construction

Improved Pistol I

Improved Pistol II

Improved Pistol III

SHIV Suppression

Stealth Satellites

SCOPE Upgrade

You Have 5 Seconds To ComplyBuild a S.H.I.V

We took a page out of the Air Force's book. Instead of exposing you own miserably armored hide you can sit in a nice and comfy air-conditioned cubicle and play video games, namely steer that SHIV. But that hasn't been build yet, so GET UP and GET MOVING! We are going to declare war on that belly I can see pushing that desk. MOVE, MOVE, MOVE!

Once the construction of a SHIV in the engineering section is complete, this trophy will unlock.

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You need to build the Foundry, followed by researching Heavy Weapons Platform in the Foundry, then build it in the Engineering section. It takes 7 days. Later you will be able to build more advanced versions. While you cannot update the chassis once you have built a certain type, weapons technology on your SHIVs gets updated automatically, as well as software updates.

Wet WorkComplete a Very Difficult abduction mission in five turns or less in Classic or Impossible difficulty

Extreme Circumstances call for Extreme Measures.

On your 2nd playthrough, be on the lookout for a Very Hard abduction mission on as small a map as possible.

Once you have found one, go back to your Save/Autosave (if you only noticed while already on mission) and equip your Squad for maximal offensive Output (Alien Grenades over Medikits). Select Support for their speed (Sprinter perk), Assault for their Run and Gun, Heavys for their Rockets. Snipers may have trouble finding a good Line of Sight, so something more mobile might be better.

With the squad forward into full cover (that works well if you did bring a Sniper with the Squadsight perk). Use the Assault troopers last to try to eliminate any opponents you couldn't kill yet.

Disregarding personal safety, rush forward for the kill - this is not the time for good tactics. Flush out the aliens quickly and dispatch them with extreme prejudice. The use of explosives is very much recommended. If it doesn't work, reload a Savegame.

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A Continental FellowWin the game from each of the 5 starting locations

"They are back, oh man, they are back."

Just as it says: Have five complete playthroughs at any difficulty level with your base on a different of the five different continents in each attempt:

North America (one of only two choices if you use the tutorial)

South America

Europe (one of only two choices if you use the tutorial)

Asia (recommended for Impossible)

Africa

Pretty much all locations are viable. Remember to reserve two of the locations that you think are best for your hardest playthroughs to get No Looking Back and Our Finest Hour and select the others as you wish.

What Wonders AwaitComplete a Research Project

You like those lady scientists in their lab coats? You'll get to see them easy enough - you bring them gooey alien stuff and then they later present what kind of goo it was. And then they promise you toys, toys, that you'll have to wait a long time for.

This is going to be one of the very first trophies you unlock. Set any research, advance a few days and you'll have this trophy.

Up And RunningBuild a base facility

You actually thought this would be different from any other military organization? If the latrines are missing, you'll have to build them. Works the same way for any other installation.
What are you waiting for? Go dig some latrines and I'll check your "achievement". It's near automatic.

During the extended tutorial you are tasked with building an alien containment facility. Once the construction is complete, the trophy unlocks.

Drums In The DeepGain access to the lowest level in your base

It's like a convulated network of steam vents down there that some crazy plumber laid out. And you don't want to dig into what makes that water into steam, really. So, yes, it does get more expensive when you dig deaper, dig me?

Once the construction of an Access Lift on the lowest level of the base is completed, this trophy will unlock.

You need a Firestorm to intercept and shoot it down. Additional weaponry and consumable boosts will help.

Once you have it shot down, send your Skyranger and defeat its Captain, just as you do with any UFO.

Off My PlanetRecover the Hyperwave Beacon

This is story-related, you cannot miss it.

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If you win the final fight against the Alien Base's Commander you will recover a new item, the Hyperwave Beacon. This will enable the research for Hyperwave Communication and eventually lead you to the next story-line mission.

And So It Begins...Complete the tutorial mission

You like those lady scientists in their lab coats? You'll get to see them easy enough - you bring them gooey alien stuff and then they later present what kind of goo it was. And then they promise you toys, toys, that you'll have to wait a long time for.

Yeah, I'll check this on your schedule, it's automatic anyways.

It will be unlocked after a few ingame days, within the extended tutorial.

The VolunteerMake contact with the Ethereal hive mind

This is a story mission. You cannot miss it.

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Once you have built the Gollop Chamber you have the option of sending one of your psionically talented soldiers wearing PSI armor into it to make contact with the alien hive mind. This will unlock the trophy and open the way to the final mission. Make sure you have achieved all other trophies you targeted for this playthrough. Once you start the final mission, there is no turning back.

Flight Of The ValkyriesWin a mission with a all-female squad. Single player only

The concept of females not being able to fight was outdated by the time weapons got a trigger instead of a sharp blade. At the latest. Have you ever seen a mother fight for her child? Ferocious, I tell you, ferocious!

Start and successfully finish a mission with female troopers only. Despite the appealing form of the alloy SHIV automated tanks are not female, and will invalidate the attempt.